The proposed renewal is for a continuation of the Biology of Infectious Diseases Training Program to train physician-scientists in infectious diseases-related translational research, both clinical and laboratory-based. The program draws on the laboratory and clinical research skills and resources of a broad group of faculty addressing questions directly relevant to infectious diseases. Funding is requested for four postdoctoral trainees per year, primarily MDs or MD/PhDs, recruited the UCSF Infectious Diseases Fellowship Program, but also PhD postdoctoral trainees from research faculty laboratories. We continue to improve our efforts to recruit underrepresented minorities and women into the program. The main program is a hands-on research experience under the close supervision of a research mentor and a career development committee selected on the basis of the research interests and goals of the trainee. Research may be at the molecular, cellular, whole animal, clinical, or population levels. Educational and training opportunities have been created to prepare individuals for research and leadership positions in academic medicine, public health, or industry in the areas of epidemiology, public health, global health, HIV/AIDS, genomics, antimicrobial resistance, microbial pathogenesis and host response, and immunology. The educational program provides for special courses, small group conferences, research conferences and seminars, coursework in immunology, microbial pathogenesis, biostatistics, epidemiology, study design, scientific writing, and ethics of scientific conduct. Emphasis is placed on personal instruction specifically designed for individual trainees and on multidiscipline interactions. The quality and effectiveness of the program is measured by the success of our trainees in 1) completion of fellowship training, 2) the number and quality of publications in peer-reviewed journals and research presentations, 3) obtaining research funding (e.g., independent research awards, K-awards or equivalent career-development awards, R01-level or equivalent awards), and 4) attainment of a research-oriented career as medical school faculty, in industry, or in the public health sector.